﻿/*
 * MIT License
 *
 * Copyright (c) 2018 Clark Yang
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of 
 * this software and associated documentation files (the "Software"), to deal in 
 * the Software without restriction, including without limitation the rights to 
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 
 * of the Software, and to permit persons to whom the Software is furnished to do so, 
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all 
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
 * SOFTWARE.
 */

using Loxodon.Framework.Utilities;
using System.Linq;

namespace Loxodon.Framework.XLua.Loaders
{
    public class FileLoader : PathLoaderBase
    {
        public FileLoader(string prefix) : this(prefix, ".lua.txt")
        {
        }

        public FileLoader(string prefix, string suffix) : base(prefix, suffix)
        {
        }

        protected override byte[] Load(ref string path)
        {
            string fullname = GetFullname(path);
            if (!FileUtil.Exists(fullname))
                return null;

            path = fullname;
            byte[] data = FileUtil.ReadAllBytes(fullname);
            if (!HasBOMFlag(data))
                return data;

            return data.Skip(3).ToArray();
        }

        protected bool HasBOMFlag(byte[] data)
        {
            if (data == null || data.Length < 3)
                return false;

            if (data[0] == 239 && data[1] == 187 && data[2] == 191)
                return true;

            return false;
        }
    }
}